The present invention relates to a dielectric ceramic composition, more particular to a dielectric ceramic composition, a ceramic capacitor using the composition and the producing method, thereof having a lower dielectric loss and stable characteristics in high frequency bandwidth, and enabling to use a base metal(e.g. Cu, W etc) or a carbon-based material (e.g. C, graphite etc) as an electrode material by allowing sintering at a low temperature, and thereby reducing the production cost.
Conventionally, a dielectric property of a ceramic provides a ceramic capacitor having larger capacitance and being more miniature in size. The ceramic capacitor may be made of a material selected from TiO2 having a rutile structure, MgTiO3, CaTiO3 and SrTiO3, having a perovskite structure and the mixture thereof.
This ceramic capacitor may be classified into a platelike type and a laminate type. The platelike type capacitor is produced by forming said material powder into some shaped body, such as pellet(disc), rod(cylinder) or chip(angular), under pressure, sintering the shaped body at 1200xc2x0 C.-1400xc2x0 C. to a sintered body, and forming electrode at each surface of the sintered body.
Also, the laminated type ceramic capacitor is produced by mixing said material powder with organic binder and organic solvent to prepare a slurry, forming green sheets from the slurry trough a doctor bladding, printing the pattern of electrode comprising of a noble metal, such as Pt and Pd, on each of the green sheets, subsequently laminating said green sheets in the thickness direction under pressure to form a laminate, and sintering the laminate at 1200xc2x0 C.-1400xc2x0 C.
As described above, however, in the conventional ceramic capacitor, the sintering process must be performed at a high temperature ranging 1200xc2x0 C.-1400xc2x0 C., to obtain the sintered body exhibiting a good electric characteristics and having a high density.
For the laminated ceramic capacitor, particularly, in the case of using a base metal as an electrode material, there has been a problem to oxidize the base metal during the sintering process, which occurs a high resistance layer formation between the ceramic layers. To avoid the problem, the noble metal material, being stable at high temperature, must be employed as an electrode material, thereby resulting in high cost.
On application of a device for high frequency bandwidth, it is preferred to have a low dielectric loss. And such device is required to have a good electric characteristics such as a quality value(Q), temperature property(this term means temperature changing ratio of the capacity), and a high reliability, However, no current dielectric material meets all the conditions.
Accordingly, there has been a need in the art to provide a dielectric ceramic composition, ceramic capacitor using the composition and the producing method to solve the problem as described above.
It is an object of the present invention to provide a dielectric ceramic composition and a producing method of the dielectric ceramic composition of having a lower dielectric loss and a stable characteristics in high frequency bandwidth and enabling to use a base metal or a carbon-based material as an electrode material by allowing sintering at a low temperature, thereby reducing the production cost.
To achieve the above object, the present invention provides the dielectric ceramic composition comprising a main component of formula SrxBa1xe2x88x92x(ZryTi1xe2x88x92y)O3 (where 0.8xe2x89xa6xxe2x89xa61; 0.9xe2x89xa6yxe2x89xa61 ) to which MnO2 of 0.05-15 wt %, at least one of 0.01-5wt % selected from the group consisting of Bi2O3, PbO and Sb2O3 and a glass component of 0.5-15 wt % are added based on the weight of the main component.
It is another object of the present invention to provide a ceramic capacitor using the composition and a method of manufacturing the ceramic capacitor.